Digging Deep for Hospital Project

I am currently back in Finland on another series of Earthmovers assignments, so I thought it would be good to take a look back at one of my last articles from the country that appeared in the magazine, brought to life on the internet, with alternative images and video.

One of Finland’s largest construction projects is well underway in the country’s capital city Helsinki. With an estimated cost of one billion euros, the Laakso joint hospital project (LYS) when completed, will eventually cover an area of 91,000 square metres.

Parts of the existing hospital which were first built 100 years ago, and now have historic preserved status, will remain and be renovated. Hospital operations in the new and refurbished buildings will start being phased in from 2027, and the entire project is expected to be completed by 2030.

Helsinki is currently experiencing a very busy period of development, with many significant and high-profile infrastructure and construction projects taking place, it seems like around every corner, excavators and tower cranes can be seen in action in the city.

The main contractor on the hospital job is Destia, and Project Manager Olli Korhonen found time in his busy schedule to show us around. Korhonen is responsible for all the excavation works and above ground infrastructure construction on the project.

A number of old buildings had to be demolished to make way for the new hospital before any of the foundation work could be started. Among the old buildings removed were, a daycare centre, a health centre, and the old gate building of the Aurora hospital on the Laaksonkentä side.

The first part of the old maintenance building has already been demolished in line with the phased plan, while the rest will be demolished at the beginning of next year. The current Laakso hospital's food preparation centre will also be demolished as soon as the catering facilities have been moved to new premises.

SRV Infra and Destia working in a joint venture, are responsible for the infrastructure and subcontracting work on site. It includes, among other things, surface and underground excavations and the excavation and construction work of the 700-metre-long connecting tunnel between the Meilahti and Laakso hospital areas.

Talking about the project Olli Korhonen, who started working in the infrastructure industry as a summer intern 21 years ago said "We started excavation works here last year, initially above ground in February and tunnel mining in May. At the moment, about 85 percent of the surface mining is complete and about two-thirds of the rock is already extracted”.

The amount of material to be excavated underground is approximately 300,000 cubic metres while above ground it’s approximately 200,000 cubic metres. A further 25,000 cubic metres is being excavated for the formation of the concrete tunnel, which will serve as the hospitals main entrance.

The tunnel which has been open cast excavated and passes through the valley’s horse-riding arena, will eventually be covered with soil and reinstated. Part of the arena is currently hosting the site offices, and acting as a compound for the storage of general building materials on site. Starting in 2027, virtually all of the hospital’s traffic to the underground parking, which will have space for 500 cars will pass through this tunnel.

A maintenance and logistics floor, a pick-up and drop-off area for patients & patient transport, and places for ambulances will also be built under the hospital.

In the tunnel entrance area, we witnessed a Kobelco SK270SRLC Short Radius hydraulic excavator, with a special crane hook attachment, placing blast mats on top of the next area to be blasted. It all looks to be painstaking work but the teams involved are well versed in the process and all the work undertaken according to the schedule.

The rock looked to be hard going to me, and Korhonen suggested that it had been of fairly uniform in quality, enabling work to progress on schedule. The site has long daily working hours starting at 7am in the morning till 9pm at night. After dark no rock blasting is allowed at ground level, but it can still take place underground until 9pm.

Korhonen explained further, “In the mornings, we do our first blasts at 7am, which means any disturbance to the old hospital, which is still in operation, is kept to an absolute minimum. The exchange of information between the hospital and the jobsite is seamless. For example, during our explosions, some of the hospital’s functions have to be stopped, such as robotics and X-ray equipment, that cannot be kept running during that time, these are the challenges we face working in close proximity to a functioning hospital”.

The quantities of explosives used in the blasting are calculated so as not to cause any damage to nearby properties. The explosive charges in the boreholes do not explode at the same time, but are deliberately delayed by a few milliseconds, causing the rock to explode in "slices". This way, the vibration is not generated by the whole explosion at once, but by a series of smaller explosions that occur every few milliseconds.

Pictured left to right: Karoliina Raekoski,  Management Intern & Project Manager Olli Korhonen

Up on a higher plateau a Volvo EC300EL, interestingly fitted with a Finnish manufactured Marttiini tiltrotator and owned by Heka Urakointi Oy, was excavating blasted rock and throwing it down to the lower level for ease of loading into trucks. A Komatsu PC290LC-11 C/W Rototilt tiltrotator from Rinne-Laturi Oy was also on hand in that work area.

In situ a Hitachi Zaxis 490LCN-7 owned by Jari Knuuttila Oy was bulking out and loading much of the blasted material on the day of our visit. On average its estimated that around 100 loads of rock are leaving the site each day. When the excavation work is complete approximately 50,000 truckloads will have left the job site. The material is being utilized for filling operations as requested by the City of Helsinki.

Rinne-Laturi Oy also had a nice example of Liebherr’s R 914 Compact wheeled excavator on site, this machine was also fitted with a Rototilt tiltrotator, doing the kind of work that highly mobile and versatile wheeled excavators are so good at.

Efforts have been made to minimize transport movements as much as possible and return loads of other building materials for the construction site are organized to further cut down on lorry movements.

On such projects one might expect to see crushing operations being conducted, so far it has not been done on this site, but it is being considered in the future, and will produce a large variety of stone in different sizes for backfilling operations, such as around drainage for example.

The largest blast operation so far was around 1,000 cubic metres, but most blasts cover around 400 cubic metres of material. Sandvik Ranger drilling rigs have been deployed widely on this project, around 5-7 of these units have been working on this site so far, these machines have been supplied by subcontractors and some of Destia’s own machines.

As a point of interest, the Ranger-class Sandvik machines are coming to an end in terms of manufacturer production and in the future new Sandvik Commando and Scorpion class models will be deployed on the project.

The drilling work has been undertaken with Destia's own equipment and with the assistance of Pro Louhinta Oy and Louhinta ja Kaivuu Janne Vuola Oy.

A nice feature on the job that resulted as a change of plans and a quick reaction from the contractors, is the excavated surface of the rock wall between the old and new hospital, apparently it was originally planned to be covered in concrete, but now it remains as a more natural rock wall feature, that visitors to the hospital will be able to admire in the future. More natural rock formations and trees have also been spared to retain a more natural finish.

Material movements on the ground at the time of our visit, were largely being handled by a Volvo L60H wheeled loader with fork attachments, a smaller Wacker Neuson compact wheeled loader was also being used for similar duties, whilst at least two tower cranes are deployed for the concrete shutter work and concrete pouring operations.

It was interesting to see the work being undertaken on this massive project, and to see the way the team are working together for the benefit of the local community, summarising Korhonen said, "All in all, we strive for an economical and as environmentally friendly operation as possible on this site. The safety of our work force and local residents are under special observation all the time."

Since this article was written work has progressed rapidly and as I understand it, a vast majority of the rock excavation has been completed. 

Big thanks as ever, go to my great friend and industry colleague Olli Päiviö of Konepörssi for organising this site visit for us.